In a medium skillet, heat oil over medium - add onion and bell pepper. Cook until the onion is tender, about 5 minutes. Scoop the mixture into a large bowl and set aside to cool for 10 minutes.

In a medium bowl, whisk together flours, baking powder, oregano, sugar, garlic powder and salt.Into the large bowl with the onion mixture, whisk in milk, feta, egg, tomato paste and olives. Pour this mixture into the dry ingredients and stir just until combined. Evenly divide the batter between the wells of 24 cup miniature muffin tin coated with nonstick spray - they should be roughly two-thirds full.

Bake until lightly browned, about 13 to 15 minutes. Remove and let sit for 5 minutes before turning the muffins out onto a wire rack.